Aldosterone reprograms promoter methylation to regulate αENaC transcription in the collecting cuct

Authors:
  • SPSøren Brandt Poulsen
    Søren Brandt Poulsen
  • KLKavee Limbutara
    Kavee Limbutara
  • RFRobert A. Fenton
    Robert A. Fenton
  • TPTrairak Pisitkun
    Trairak Pisitkun
  • BCBirgitte Mønster Christensen
    Birgitte Mønster Christensen
  • MGMegan M. Greenlee
    Megan M. Greenlee
  • JMJeremiah D. Mitzelfelt
    Jeremiah D. Mitzelfelt
  • BDBillie Jeanne Duke
    Billie Jeanne Duke
  • OAOtor Al-Khalili
    Otor Al-Khalili
Publisher website
Google Scholar
Abstract
Aldosterone increases tubular Na+ absorption largely by increasing α-epithelial Na+ channel (αENaC) transcription in collecting duct principal cells. How aldosterone reprograms basal αENaC transcription to high-level activity in the collecting duct is incompletely understood. Promoter methylation, a covalent but reversible epigenetic process, has been implicated in the control of gene expression in health and disease. We investigated the role of promoter methylation/demethylation in the epigenetic control of basal and aldosterone-stimulated αENaC transcription in mIMCD3 collecting duct cells. Bisulfite treatment and sequencing analysis after treatment of the cells with the DNA methyltransferase (DNMT) inhibitor 5-aza-2′-deoxycytidine (5-Aza-CdR) identified clusters of methylated cytosines in a CpG island near the transcription start site of the αENaC promoter. 5-Aza-CdR treatment or small interfering RNA-mediated knockdown of DNMT3b or methyl-CpG-binding domain protein (MBD)-4 derepressed basal αENaC transcription, indicating that promoter methylation suppresses basal αENaC transcription. Aldosterone triggered a time-dependent decrease in 5mC and DNMT3b and a concurrent enrichment in 5-hydroxymethylcytosine (5hmC) and ten-eleven translocation (Tet)2 at the αENaC promoter, consistent with active demethylation. 5-Aza-CdR mimicked aldosterone by enhancing Sp1 binding to the αENaC promoter. We conclude that DNMT3b- and MBD4-dependent methylation of the αENaC promoter limits basal αENaC transcription, in part by limiting Sp1 binding and trans-activation. Aldosterone stimulates the dispersal of DNMT3b and recruitment of Tet2 to demethylate the αENaC promoter to induce αENaC transcription. These results disclose a novel epigenetic mechanism for the control of basal and aldosterone-induced αENaC transcription that adds to previously described epigenetic controls exerted by histone modifications.

This publication has 29 references indexed in Scilit: